from math import sqrt
x1, y1, x2, y2 = [float(i) for i in input().split(" ")]
print("{:.8f}".format(sqrt( (x2 -x1) ** 2 + (y2 - y1) ** 2))) from math import sqrt float(i) for i in input().split(" ") for i in input().split(" ") i input().split(" ") ().split () input split " " for i in input().split(" ") float(i) float i x1, y1, x2, y2 = [float(i) for i in input().split(" ")] x1 [float(i) for i in input().split(" ")] y1 x2 y2 print("{:.8f}".format(sqrt( (x2 -x1) ** 2 + (y2 - y1) ** 2))) print "{:.8f}".format(sqrt( (x2 -x1) ** 2 + (y2 - y1) ** 2)) "{:.8f}".format "{:.8f}" format sqrt( (x2 -x1) ** 2 + (y2 - y1) ** 2) sqrt (x2 -x1) ** 2 + (y2 - y1) ** 2 (x2 -x1) ** 2 x2 -x1 x2 x1 2 (y2 - y1) ** 2 y2 - y1 y2 y1 2 x2, y2 = [float(i) for i in input().split(" ")] [float(i) for i in input().split(" ")] x2 x1, y1, x2, y2 = [float(i) for i in input().split(" ")] [float(i) for i in input().split(" ")] x1 y1, x2, y2 = [float(i) for i in input().split(" ")] [float(i) for i in input().split(" ")] y1 y2 = [float(i) for i in input().split(" ")] [float(i) for i in input().split(" ")] y2
from math import sqrt
x1, y1, x2, y2 = [float(i) for i in input().split(" ")]
print("{:.8f}".format(sqrt( (x2 -x1) ** 2 + (y2 - y1) ** 2)))